So lately my car has been running on 91 octane because if I don't it pings a bit on acceleration and sometimes it will on cruising highway speeds. Took a trip out to Cali and my average MPG highway was 15-18 mpg per the gauge on the car. Not sure if the pinging and MPG are a common issue. So just trying to see where I should start looking to troubleshoot.
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Fuel issues + low MPG + 91
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65 I would be hitting 15, 18 would be at 75 mph. Yesterday I put half a tank of 91, drove to work and home 10 miles each way freeway at 65 and turn the car on today and sitting just above empty. 88 325i
I have a small leak at the valve cover that is a slow leak but holds oil well.
I was thinking it was a fuel Injector, or pump going bad or a filter. Is a injector rebuild something I can do on my own?
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What are your mods? Could be a number of things, from valve contact to bad injectors. An easy test is to take an IR temp gun to each of the primaries as it's running. A large temp difference will point you toward the cylinder that is having issues, if it's just one cylinder and not an issue down the line (fuel pump/filter/timing belt slipped, etc)
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Originally posted by Seawolf View PostCheck your Fuel pressure regulator vacuum line (the thin vacuum line that runs from the FPR to the inlet manifold) if your FPR is iffy fuel will get into that line and overfuel the engine.
How's the engine run generally ? Good idle ? Pulls well ?
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Originally posted by squidmaster View PostWhat are your mods? Could be a number of things, from valve contact to bad injectors. An easy test is to take an IR temp gun to each of the primaries as it's running. A large temp difference will point you toward the cylinder that is having issues, if it's just one cylinder and not an issue down the line (fuel pump/filter/timing belt slipped, etc)
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